The invention relates to a conveyor device for can bodies in a can welding machine having an arm around which the can bodies are rounded and at least one endless conveying track which is guided over guide devices and a driving wheel and comprises a run parallel to the arm in order to convey the can bodies along the arm in the direction of a welding station.
In a known can welding machine which is equipped with such a conveyor device (CH-PS 621 499), a bearer is disposed above the arm and parallel thereto, the lower marginal region of which bearer is constructed in the form of a Z-rail to guide the longitudinal edges of the can bodies. Disposed one at each side of the bearer is a conveying track which consists of an endless flat-link chain with pusher dogs disposed spaced apart. The two flat-link chains each run in a vertical plane which extends parallel to the common central plane of the arm and of the bearer. The lower run of each of these two conveying tracks runs immediately beside the Z-rail in such a manner that the pusher dogs of the two conveying tracks can engage in pairs behind the rear edge of each can body regardless of whether this has a large or a small diameter. These two conveying tracks each have a rear and a front guide roller; the front guide rollers are disposed in the vicinity of a welding station in which the longitudinal seams of the can bodies are welded together by means of a pair of electrode rollers. In the region of the rear guide rollers, the said conveying tracks overlap a pair of preceding conveying tracks, each of which likewise consists of a roller chain and pusher dogs arranged spaced apart and which take over the can bodies from a rounding apparatus. These preceding conveying tracks are each disposed at one side of the said arm in an inclined plane which is substantially radial with respect to the arm. The pusher dogs of these two preceding conveying tracks extend so far away from the associated conveyor chain in each case that they are capable of pushing forwards can bodies of different diameters by engaging behind their rear edge.
In similar conveyor devices on can welding machines, it is also known (US-PS 4 497 995 and US-PS 4 574 176) to mount guide rollers and tension rollers, round which an endless conveying track is wrapped in the form of a chain equipped with pusher dogs, on a stationary mounting plate which comprises a plurality of sets of holes so that the said rollers can be disposed at different distances away from a Z-rail and the position of the whole conveyor track can be adapted to can bodies of different diameters as a result.
In all known conveyor devices which belong to the type described at the beginning or are comparable therewith, the range within which an adaptation to can bodies of different diameter or different length is possible with little expenditure on labour, is comparatively narrowly limited. If conversions are possible at all within a larger range of diameters or lengths of the can bodies, they require a time-consuming conversion of large parts of the can welding machine.
It is therefore the object of the invention to develop further a conveyor device for can bodies on a can welding machine in such a manner that it can be adapted with little effort to can bodies within a large range of diameters and lengths.
Starting from a conveyor device of the type described at the beginning, the problem is solved, according to the invention in that
the guide devices are mounted on a track carrier and form with this and with the associated conveying track, a unit adapted to the length of the can bodies and PA1 this unit as a whole is interchangeably secured to a sliding carriage which is adjustable at least substantially radially to the arm. PA1 each conveying track to have associated with it, its own track carrier and its own sliding carriage and PA1 the two sliding carriages of each pair to be adjustable on guides which extend one at each side of a longitudinal median plane of the arm, obliquely upwards in the direction of this.
As a result, the possibility is afforded of dividing a multiplicity of can bodies of different lengths, which are to be welded on a can welding machine, into a plurality of ranges of length with each of which there is associated at least one unit consisting of track carrier, conveying track and associated guide devices. The track carriers provided for different ranges of can length can be exchanged for one another with a few movements of the hand and each track carrier can be adjusted by the associated sliding carriage in such a manner that its arrangement is adapted in the optimum manner to can bodies of any desired diameter within the working range of the machine. There is also the possibility of retrofitting a machine which was originally equipped with track carrier units of simple construction, with more highly developed track carrier units, for example with those which have electronically controlled individual drives.
If at least one pair of endless conveying tracks is provided in the conveyor device according to the invention, which act jointly and simultaneously on the can bodies, then it is advisable for
This saddle-like arrangement of the guides below the arm, improves the accessibility of the can bodies which are being conveyed along the arm. The possibility of moving the conveying tracks radially away from the arm by means of the sliding carriages to which the track carriers are secured, also facilitates the mounting and removal of the track carriers together with all the associated components
It is further an advantage if guide elements for the can bodies are adjustably secured to one of the sliding carriages. Thus the additional advantage is achieved that the said guide elements, together with the sliding carriage on which they are supported, can be adjusted away from the arm as a result of which this becomes accessible all round. Accordingly, operational disturbances, during which can bodies have piled up on the way to the welding station, can be eliminated particularly easily and quickly.
Preferably, the two sliding carriages of each pair of sliding carriages each have their own adjusting drive associated with them for a precise adjustment according to the diameter of the can bodies and at least one of the two sliding carriages of each pair of sliding carriages, which is disposed at a side of the can welding machine easily accessible to an operator has associated with it a rapid-motion drive which can be actuated independently of its adjusting drive, to expose the arm. The rapid-motion drive likewise contributes to accelerating the conversion of the machine and the elimination of operational disturbances.
It is further an advantage if each track carrier is mounted on a transmission unit which is secured to the associated sliding carriage and which comprises a driving shaft which can be coupled to the driving wheel
If the conveying tracks are arranged in pairs in the manner described, it is further advantageous for the driving shafts on the two sliding carriages each to be able to be driven through a cardan shaft from a common motor.